1,3,4-thiadiazole-5(4h)-one derivatives

ABSTRACT

Pesticidal compositions are disclosed which contain as active ingredients 1,3,4-thiadiazole-5(4H)-one derivatives of the formula WHEREIN R1 and R2 each represent lower alkyl, R3 represents lower alkyl optionally substituted by lower alkoxy or lower alkylthio, and X represents oxygen or sulphur; THESE COMPOSITIONS ARE USEFUL AS SOIL DISINFECTANT AND FOR CONTROLLING INSECTS, SPIDERS, SOIL FUNGI AND NEMATODES.

United States Patent of New York No Drawing. Filed Nov. 23, 1966, Ser. No. 596,445

0 Claims priority, application Switzerland, Dec. 1,1965,

16,577/65 Int. Cl. C07f 9/24, 9/44 US. Cl. 260306.7 13 Claims ABS'IRACT OF THE DISCLOSURE There are disclosed derivatives of 1,3,4-thiadiazole- (4H)-one of the formula /s R1\ O=I C-X-Rs /ii R20 S wherein R is lower alkyl, lower alkoxy optionally substituted by lower alkoxy or halogen, or phenyl;

R is lower alkyl optionally substituted by lower alkoxy or halogen;

R is alkyl having from 1 to 6 carbons optionally substituted by lower alkoxy or lower alkylthio; and

X is oxygen or sulphur.

These compounds have fungicidal, insecticidal, acaricidal and nematocidal properties and are therefore useful for soil disinfection.

The present invention relates to new 1,3,4-thiadiazole- 5(4H)-one derivatives and processes for their preparation. It also relates to new pesticidal compositions, such as soil disinfectant, acaricidal and insecticidal compositions, containing these new compounds, as well as to new processes for the disinfection of soil and for the combatting of pests, such as insects and acarinae, by using the new compounds or compositions containing them. It further relates to processes for the preparation of the novel compositions.

It has now been found that 1,3,4-thiadiazole-5 (4H)- one derivatives of the general formula wherein R represents a lower alkyl group, a lower alkoxy group which is optionally substituted by lower alkoxy or halogen, or a phenyl group,

R represents a lower alkyl group optionally substituted by lower alkoxy or halogen, R in the general Formula I represents an aliphatic hybe substituted, and

X represents oxygen or sulphur,

have excellent fungicidal (soil), insecticidal, acaricidal and in particular nematocidal properties so that they are valuable, in particular, for soil disinfection. The new compounds are also suitable for combatting pests which threaten stores and health.

By lower alkyl groups symbolized by R and R in the general Formula I are meant those with 1 to 4 carbon atoms such as the methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, secondary and tertiary butyl group. By lower 3,523,951 Patented Aug. 11 1970 ice . e,g. by a lower alkoxy or a lower alkylthio group having from 1 to 4 carbon atoms.

Preferred compounds are those wherein R is methyl, methoxy, ethoxy, isopropoxy, methoxy-ethoxy, chloroethoxy or phenyl; R is methyl, ethyl, isopropyl, methoxy ethyl, or chloro ethyl; R is lower alkyl with 1 to 6 carbon atoms; lower alkoxy-lower alkyl with a total number of carbon atoms of from 2 to 6; or lower alkylthio-lower alkyl with a total number of from 2 to 6 carbon atoms.

By soil disinfection is meant the destruction of insects and fungi living in the soil and in particular of nematodes.

The new 1,3,4-thiadiazole-5-(4H)-one derivatives of general formula I are obtained according to the invention by reacting a thiocarbazic acid ester of general Formula II:

wherein R R R and X have the meanings given in Formula I, with phosgene, the reaction being performed in the'presence of a solvent or diluent which isinert to the reaction components and within a temperature range of 0 to 100 C. Phosgene is added to the reaction either as gas or dissolved in an inert solvent, at temperatures between 0 and 30 C. On completion of the addition of phosgene, the reaction mixture is heated to 30 to 100 C., preferably to 30 to The hydrogen chloride formed during the reaction can, if necessary, be bound by means of a tertiary amine such as triethylamine, pyridine, etc.

Suitable solvents or diluents for the process according to the invention are principally aromatic hydrocarbons such as benzene, toluene, xylene, or chlorinated hydro carbons such as chlorobenzene and chloroform.

As thiocarbazic acid esters of general Formula II for the process according to the invention, the methyl, ethyl, n-propyl, isopropyl, 2-methoxyethyl, 2-ethoxyethyl, 2-isopropoxyethyl esters, the butyl, amyl and hexyl esters of the following monothiocarbazic acids can be used:

3-(dimethoxy-phosphinothioyl)-thiocarbazic acid, 3-(diethoxy-phosphinothioyl)-thiocarbazic acid, 3-(di-isopropoxy-phosphinothioyl)-thiocarbazic acid, 3- (bis-2-methoxyethoxy-phosphinothioyl) -thio carbazic acid, 3-(bis-2"chlorethoxy-phosphinothioyl)-thiocarbazic acid, 3-(methylmethoxy-phosphinothioyl)-thiocarbazic acid, 3-(methylethoxy-phosphinothioyl) -thiocarbazic acid, 3-(phenylmethoxy-phosphinothioyl)-thiocarbazic acid, 3-(phenylethoxy-phosphinothioyl)-thiocarbazic acid,

as well as of the following dithiocarbazic acids:

3- (dimethoxy-phosphinothioyl) -dithiocarbazic acid, 3-(diethoxy-phosphinothioyl)-dithiocarbazic acid,

3-(di-isopropoxy-phosphinothioyl)-dithiocarbazic acid,

3-(bis-2'-methoxy-ethoxy-phosphinothioyl)-dithiocar bazic acid, r v 3- (bis-2'-ch10rethoxy-phosphinothioyl) -'di'th'ioca"rbazic acid, 3-(methylmethoxy-phosphinothioyl)dithiocarbazic acid, 3-(rnethylethoxy-phosphinothioyl)-dithiocarbazic acid, 3-(phenylmethoxy-phosphinothioyl)-dithiocarbazic acid, 3- (phenylethoxy-phosphinothioyl) -,dithio carbazic' acid,-

The esters of the monothiocarbazic acids aretherefore always the O-esters. s The monothiocarbazic acid esters (if-Formula II areob tained by reacting a correspondingly substituted 2-phosphinothioyl hydrazide with a xathogenate of the general formula mo -C-s-r;

while splitting oif potassium hydrogen sulphide, or by reacting such a hydrazide with a compound of the general formula i Ra-O-(f-S-CHz-C O ONa while splitting off thioglycolic acid. The dithiocarbazic acid esters are obtained direct by reacting a correspondingly substituted 2-phosphinothioyl hydrazine with carbon disulphide, potassium hydroxide and an alkylating agent, preferably an alkyl halide. The monoand also the dithiocarbazic acid esters can be obtained by reacting a phosphinothioyl halide with a thioor dithiocarbazic acid ester in the presence of an acid acceptor.

It is indeed known that thioand dithiocarbazic acid esters unsubstituted in the 3-position can be cyclised with phosgene to form thiadiazolones. This is relatively easy to understand as the unsubstituted amino group of these carbazinates has a strongly basic character as is shown, for example, in the formation of salts with mineral acids and it is thus a suitable point of attack for the carbonic acid halide. [Guha and Guha, CA. 21 3199'; Z. 1927 II 1705; J. Ind. Chem. Soc. 4, 239 (1927)].

In the 3-phosphinothioyl-thioand dithiocarbazic acid esters of Formula II however, there are phosphorus amides not having basic properties so that no further reaction with an acid halide was to have been expected.

The ease of ring closure to form the claimed compounds of the Formula I by the action of a carbonic acid halide such as phosgene, therefore, could in no way have been expected.

In the purified state, the new thiadiazole-5-(4H)-one derivatives of general Formula I are colourless oils which dissolve well in organic solvents but are insoluble in water. The new compounds have only very slightly toxicity for plants and warm blooded animals, for which reason their use is of the greatest importance in the protec tion of plants and stores and also in combatting pests which threaten health.

The range of action of the active substances mentioned and, in particular, the insecticidal and acaricidal action, is improved by admixture with synergists and auxiliaries having a similar action such as succinic acid dibutyl ester, piperonyl butoxide, olive oil, peanut oil, etc. In the same way, the insecticidal action can be substantially widened and adapted to given circumstances by the addition of other insecticides such as the esters and amines of phosphoric acid, phosphonic acid, thioand dithio-phosphoric acid, carbamic acid esters, halogenated hydrocarbons, analogues of DDT active substance, pyrethrins and synergists thereof.

The following examples serve to illustrate the process according to the invention. Where not otherwise stated, parts are given therein as parts by weight and the temperatures are in degrees Centigrade. i

EXAMPLE 1 =2-ethoxy-'4-( diethoxy-phosphinothioyl 1 ,-3,4-thiadiazole- 715 parts by volume of a solution of phosgene in benzene containing 240 parts of phosgene, is added dropwise to avsolution" of 432parts of '3-diethoxy-phosphinothioyl thiocarbazic. acid-O-ethyl esterv (MP. 5849) in 800 parts'by volume of anhydrous benzene while slightly cooling, the addition being made so quickly that the reaction temperature remains between 10 and'20.IThe whole is stirred for 16 hours at room temperature and is then gradually heated within 1 hour to reflux temperature. After refluxing for 1 hour, the solvent is' distilled off and 500 parts of Water are added to the residue. The oil which separates out is taken up in ether," the ethereal solution is extracted first with dilute sodium bicarbonatesolution and then with water and dried over sodium sulphate. After distilling off the ether, the residue is fractionated under high vacuum. 410 parts of 2 ethoxy-4-(diethoxy-phosphinothioyl)-1,3,4-thiadiazole-5(4H)-one distill at 120- 122/0.05 torr as a colourless oil (yield 86%).

EXAMPLE 2 2-methylthio-4-(diethoxy-phosphinothioyl)-1,3,4- thiadiazole-S (4H )-one parts by volume of a solution of phosgene in benzene containing 20 parts of phosgene are added quickly, without external cooling to a slurry of 28 parts of 3-diethoxyphosphinothioyl-dithiocarbazic acid methyl ester (M.P. 104l05) in parts by volume of anhydrous benzene. The temperature of the mixture rises from 16 to 28 and, while gas is developed, first a yellow solution is formed which, however, becomes colourless after one hour. Excess phosgene and benzene are then distilled off under water jet vacuum. Further working up according to Example 1 yields 21 parts of 2-methylthio-4-(diethoxyphosphinothioyl)-1,3,4-thiadiazole-5(4H)-one as a colourless oil. It boils at 123124/0.02 torr (yield 70%).

EXAMPLE 3 2-isopropoxy-4-(diethoxy-phosphinothioyl)-1,3,4- thiadiazole-S (4H)-one parts of phosgene are introduced at 5 to 15 to a cooled solution of 355 parts of 3-diethoxy-phosphinothioylthiocarbazic acid-O-isopropyl ester (M.P. 81-82") in 1000 parts by volume of anhydrous benzene. The whole is stirred for 2 hours at room temperature, then heated within 1 hour to reflux temperature whereupon it is refluxed for 1 hour. Further working up according to Example 1 yields 315 parts (81% yield) of 2-isopropoxy-4- (diethoxy-phosphinothioyl)-1,3,4-thiadiazole-5 (4H) one as a colourless oil. It boils at 124/ 0.04 torr.

EXAMPLE 4 2-(2'-methoxy-ethoxy)-4-(dimethoxy-phosphinothioyl)- 1,3,4-thiadiazole-5 (4H)-one given in the following table are obtained by the methods described in Examples 1 to 4 by reacting the corresponding thioor dithio-carbazic acid esters with phosgene:

The concentration of active substance in the agents according to the invention is between 0.01 and 80%, in particular between 10 and 80%. In addition to the active Boiling point or Yield in R1 R R; X melting point percent C H; C2H5 C H; N0; distlllable CH C3115 CH3 8 .c... 0 C H; O 0 H C H; O 104l06/0.005 torr 71 (EH 0 CH CzHs O 115117/0.007 torr- 30 C H 0 CH n-C H1 0 13l132/0.008 torr 52 CH O CH iSO-C3H O 113114/0.005 torr. 7O CHgO CH n-C Hg O 125/0.001 torr 1 85 C H3 0 C H C H S 140142/0.02 tom 37 CHgO CH CzHs S 125/0.001 torr 1 94 CHaO CH n-C H S d0-.- '91 CH O CH OH3OC1H4 S CHQO CH CzHsOCgHr S CHJO CH iS0-CaH7OC2H4 0 01130 CH3 CH SC2H4 S CzH O C5115 C H 0 115-116/0.03 torr 65 Cal-I50 C 115 Il-C H7 0 128-13(]/0.05 13011 68 H CgHr, n- C 4H9 O 131-132/0.03 torr 65 CzH5O CzHs lSO-CqHn O 13013l/0.015 torr 72 C H O CzH5 sec.C H 0 1 50 CzHa 0 CzHs I1- C5Hn O 137-139/0.003 tOIT. 73 CgH5O CzHs n-CaHm O 156/0.001 torr 67 0,1150 CzHs 2 5 S 133-134 /0.01 tOI'l'- 74 01H]; 0 CzHg n- C H S 125/0.0005 torr l 95 C 115 0 CzHa 1S0 C3117 S 126-127/0.008 tOIT 86 CzHs CzH5 CHaO-Cfl-L O 142/0.015 tOII- 73 CH O O2H5 C H O 07114 O 1350 C2115 lS0-C H7O C2134 C 2 50 CzHs C2 4 S 2 50 O2H5 2 50 2 S CzH O CgH5 iSO-CaH'rO Cal-I4 S CzH5O C2115 CaHsS CzH; S CZHEO CzHs iS0-C H7S CzH4 S 1so-C H10 1so-C H CH3 0 112-116/0.015 torr- 88 iso-C H O iSO-C H7 iso-C H O 122-124/0.004 torr- 55 180 C 117 iSO- C H7 C 3 S 50451 isoO;H O iso-O H CH S CzH S CHaOCHgCHgO CHgOCHflCH: CH 0 38 CHgOCHgCHzO CHgOCHgCHg CH S (31H; S 39 ClCHgCHzO ClCHzCHg CH 0 135/0.005 torr--- 4O ClCHgCHzO CICHgCH: CH3 S NOt distillable 41 C2 5 0113 s o 42 0 H; 150-08111 s 185/0.005 torr Both for soil disinfection and for the combatting of stances are stable, cause no irritation to skin and mucous v membranes and so can be applied to the earth to be treated, e.g. by mixing therewith, pouring thereon, injection, etc., in the form of sprinkling agents, granulates, dispersions and solutions. The mode of application and form of agent depend particularly on the type of soil meant to be combatted, the climate and earth conditions. As the new active substances are not phytotoxic and do not have an adverse effect on the germination of seeds, they can be applied without consideration of a so-called Waiting time and in already established crops.

, To combat insects and spiders, the active substances of the general Formula I are applied in the form of dusts or sprinkling agents, granulates, dispersions, solutions and aerosols. The soil disinfectants and insecticidal agents according to the invention are produced in the known way byintimately mixing and milling the active substances with suitable carriers, optionally with the addition of dispersing agents or solvent-s which are inert to the active substances. The dispersions mentioned in the above text are obtained from concentrates of active substance such as wettable powders, pastes, emulsions, by dilution with water to the concentration of active substance desired for use.

substances, such agents can also contain other biocidal active substances such as other nematicides, fungicides and insecticides, also bactericides, fungistatics, bacteriostatics, etc.

For soil disinfection, substances having great water and citrate solubility, fertilisers, plant growth promoting substances or herbicides, can be admixed in the solid application forms. For this purpose, it is also of advantage to use halogenated hydrocarbons as solvent such as 1,2- dibromo 3 dichloropropene, mixtures of 1,2 dichloropropane and 1,3 dichloropropene, the instantaneous nematocidal action of which is valuable complement to the long lasting action of the active substances according to the invention.

The following forms for application serve to illustrate the present invention; where not otherwise stated, parts are given as parts by weight.

DUST

To produce (a) a 10% and (b) a 2% dust, the f0llowing substance-s are use:

10 parts of 2-ethoxy-4-(diethoxy-phosphinothioyl)- 1,3 ,4-thiadiazole-5 (4H -one,

5 parts of highly dispersed silicic acid,

parts of talcum.

2 parts of 2-methylthio-4-(diethoxy-phosphinothioyl)-1,

3,4-thiadiazole-5 (4H)-one,

1 part of highly dispersed silicic acid,

97 parts of talcum.

The active substances are mixed and milled with the carriers. The dusts obtained are suitable e.g. for combatting cockroaches and ants in houses. To disinfect soil, these dusts can also be worked into the soil.

SPRINKLING AGENT To produce a 25% sprinkling agent, the following substances are used:

The active substance is intimately mixed with the emulsifier and the kieselguhr, and then the calcium sulphate is mixed in. A sprinkling agent is obtained which is particularly suitable for soil disinfection.

WETTABLE POWDER To produce (a) a 50% and (b) a 10% wettable powder, the followng components are used:

10 parts of 2-methoxy-4-(dimethoxy-phosphinothioyl)- 1,3,4-thiadiazole- 4H) -one,

3 parts of a mixture of the sodium salts of saturated fatty alcohol sulphates,

5 parts of naphthalene sulphonic acid/ formaldehyde condensate,

82 parts of kaolin.

The active substances are intimately mixed with the additives in suitable mixers and milled on corresponding mills'and rollers. Wettable powders are obtained which can 'be diluted with water to any concentration desired. Such suspensions can be used for both soil disinfection and to combat ticks in pets and domestic animals.

EMULSION I CONCENTRATE To produce a 25% emulsion concentrate,

25 parts of 2-propoxy-4-(dimethoxy-phosphinothioyl)-1,

3,4-thiadiazole-5(4H)-0ne,

2.5. parts of epichlorohydrin,

5 parts of an emulsifying combination (alkylaryl polyethylene glycol/alkylaryl sulphonate, calcium salt),

67.5 parts of xylene are'mixe'd together, This concentrate can be diluted with water to form emulsions having concentrations suitable for the protection of plants and stores. In particular, such emulsions are suitable for combatting ticks in pets and domestic animals.

8 I claim: 1. A 1,3,4-thiadiazole-5(4H)-one of the formula 5 R1\ O=(IJ fiX-R V I s wherein R is lower alkyl, lower alkoxy, lower alkoxy substituted by lower alkoxy or halogen, or phenyl;

R is lower alkyl, or lower alkyl substituted by lower alkoxy or halogen;

R is an alkyl group having from 1 to 6 carbon atoms which can be substituted by lower alkoxy or lower alkylthio; and

X is oxygen or sulfur.

2. A 1,3,4-thiadiazole-5(4H)-one of the formula R is methyl, methoxy, ethoxy, isopropoxy, methoxyethoxy, chloro-ethoxy or phenyl;

R is methyl, ethyl, isopropyl, methoxy-ethyl, or chloroethyl;

R is lower alkyl with 1 to 6 carbon atoms, lower alkoxylower alkyl with 2 to 6 carbon atoms, or lower alkylthio-lower alkyl with 2 to 6 carbon atoms; and

X is oxygen or sulfur.

3. A compound as defined in claim 1 wherein R is methoxy, R is methyl, R is methyl, and X is oxygen. 4. A compound as defined in claim 1 wherein R is methoxy, R is methyl, R is propyl, and X is oxygen. 5. A compound as defined in claim 1 wherein R is 1 neth0xy, R is methyl, R is 2-methoxyethyl, and X is oxygen.

6. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is methyl, and X is oxygen.

7. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is ethyl, and X is oxygen.

8. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is methyl, and X is su'lfur.

9. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is isopropyl, and X is oxygen. 10. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is propyl, and X is oxygen.

11. A compound as defiend in--claim 1 wherein R is ethoxy, R is ethyl, R is ethyl, and X is sulfur.

12. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is isopropyl, and X is sulfur. 13. A compound as defined in claim 1 wherein R is ethoxy, R is ethyl, R is isopropoxyethyl, and X is oxygen.

' References Cited 7 ALTON D. ROLLINS, Primary Examiner US. Cl. X.R. 424-200, 187; 260-455, 923 

